Treament of transparent material



XR 1566239 5R l Patcnted nec. 1$,

CHASE-LES E. SWETT, OF WEST BO IBUR' Y, AND WILLARD 3. SWEET, OF WORCESTER,

UNITE srn'rss", PATENT-OFFER MASSACHUSETTS, ABSIGBOBS T0 'UHXTED STATES. EEWIQLOPE comm, OI SPRINGFIELD, HASMCHUSETTS, ABOBPOB-ATIOH 0? mm 7 I rssan'mm or cameraman:

in 0 Drawing.

Commonwealthof Massachusetts, and Wm" LARK) E. SWIFT, a citizen of the United States, residing at Worcester, in the-county of Worcester and Commonwealth of Messachusetts, have invented a new and useiul Improvement in the Treatment of Transparent vMate-rial, of which. the following is a specification. c

The present invention relates; to, the

treatment oi transparent material, for the purpose of reducing the glare, or reflection of light, from its surface. is particularly applicable to the treatment of such material as is used for the transparent patches or panels of so-c'alled windovi envelopes,- i, e., the type of envelo .e -having an opening therein, over w rich is cemented a covering of glassine paper, or other similar transparent or semi-transparent material. Y

In window envelopes as thus manufactured, a troublesome feature is the glare or reflection of light from the surface of the patch or panel, this giving rise to obi'ection on the part of those required to iandlo numbers of such envelopes, as for instance in the sorting of mail, particularly when the light falls at, a small angle from the plane of the surface. -The reduction or elimination of this glare, without sub-' stantial sacrifice of the transparenct of the patch or panel, is the primary object of the present invention, the same involving a mode of treatment for the surface of the glnssine paper, or other similar material, which leaves said surface in a substantially iuatt or non-glare condition.

This treatment, as contemplated by the present invention, consists, generally, in sub'ecting the surface of the panelvmater'ial to rictional'or rubbins action in the presence thereon of a suitable lubricant; in this way, the character of the surface is so altered, in some degree presumably by the lifting or disarrangement of its fibres, that the glare therefrom is materiall reduced, without impairment however o the visibility or light transmitting properties of the material. In carrying out the process,

the lubricant may be applied either to the The invention other than them above describe employedin a manner the same or similar to Application no nu im :1, 122:. Serial x. 0.44;.

nmterial or to the device by which the rub b'ing or friction is produced; and we have discovered that a suitable and desirable lubricant, for the purpose described sistsof a mixture of sulphonated oil and water, with or without the addition of glycerine, or a mixture of alcohol, water and acetate of potash or soda. W e have also discovered that the presence of some water in the composition of whatever-lubricant is used is quite desirsble, since water, tends to soften. the fibres of the material and thereby promotes any change inthefihrons ture which may takeplaee Qnthe other band, the presence of too iniichwater in the,

lubricant is undesirable,-= on account of the t'cndencv of the 'material to warp and cookie when wet.

, con 1 When subjected as above described to lubricated frictional treatment, the surface of the material is left in a matt and substantially glarelezs condition, even after all traces of the lubricating substances havev been washed "05,-:- a circumstance which rcndcrs the material thus treated especially adapted to the manufacture of window envelopes, since said condition is attained in the absence of any-glsre-deadening deposit, such as might tend to flake 05' or become bruised when subjected to handling in a window envelope machine.

Our invention residw in the mode of treatment abovev described, by which the material is subjected to frictional or rubbing actionin the PTESSIICE. of asuitable lubricant; it is obvious that lubricatin mixtures d may be that above described, and we do not limit oarselves'to thense of said specified substances or materials, except as set certain of the nppended claims. We claim:

forth in 1. The herein described process of treab ing transparent panel material, which consists subjecting the surface of said material to lubricated friction. v I

'2. In the production of a matt "or substantially glareless' surface for trans arent. panel material, the 1m rove-ment whlc con-.

sists in frictionally ru hing the material in the presence of a lubricant.

3: In he production of a matt or substantially glareless sari-we for transparent limi ud quantity ciwater.

4. In the production of a matt. o r snl panel material, the im rovement which consists in fnchonnlly ru bmg the material in the instance of a lubricant contain ng a stantially glarelcss surface for transflmrent panel material, the improvement \VillC'l eonsists in frictionally rubbing the material with an aqueeus mixture which has a softening action material.

5. In the production of -a matt or substnntially glareless surface for transparent on the fibers 9f said' panel material, the!improi'cnwnt which (011- sists in frictionall'y rubbing l-i0 material in the pmscn'qe of n lubritap; containing sub plxomxtedo1l. f v 6. In thmpvoduction 0i a matt or substantial y glarclzxai surface for transyarent panel material, the imPFOVK'XnPX-lt whic x c'0n-. sxsts Ill irrationally rubbing the materialwith a nuxture containing water and sul phonntml oil.

CHARLES E swam; wmmnn E. SWIFT; 

